Field of The Invention
The present invention relates to a UV curable coating composition and a method for manufacturing UV-cured hard coatings.
Description of The Related Art
Epoxysilane based coating are known to be used in the optical industry for providing abrasion resistant coatings. However, to be efficient, the coating must not only have abrasion resistant properties but also good adhesion properties to the support. A coating composition is generally specifically adapted to one type of substrate and does not provide sufficient adhesion properties on other substrates. For example, in the optical industry, two types of coatings are used to satisfy the condition of good adhesion on both thermoplastics and thermosets: an acrylate based coating will typically provide good adhesion on thermoplastic like substrates while an epoxy based coating is known to provide good adhesion on thermoset like substrates. Primers have also been provided for improving the adhesion of abrasion resistant coatings on different substrates. However, by using such a solution an additional layer has to be applied between the substrate and the abrasion resistant coating, resulting in increasing the manufacturing costs.
Therefore, there is a need to provide optical laboratories with a UV curable monolayer coating that can be applied to ophthalmic lenses that exhibit a high level of abrasion and scratch resistance as well as good adhesion properties regardless the nature of the substrate, in particular to both thermoplastic and thermoset lens substrates, without the need of a primer.